The most heartbreaking sequence in 'Blue Planet II': A pilot whale mourning her calf

This Saturday’s episode of BBC America’s Blue Planet II takes us out into the “big blue,” the open ocean. “Here there is nowhere to hide and little to eat. It’s the marine equivalent of a desert,” narrator Sir David Attenborough says at the top of the hour. If you’ve been waiting to see more whales in the series, this installment is for you. But it won’t all go down easily.

As you see in the sneak peek above, the crew captured what producer Mark Brownlow describes as “a profoundly tragic story” — a pilot whale refusing to let go of the body of her dead newborn. His team worked closely with a cameraman based in the Canary Islands who’s been filming pods of pilot whales for many years and has witnessed, a couple of times, mothers holding on to their dead infants for days. “Pilot whales have such large brains, so filled with the cells called spindle cells, which scientists know are responsible for conscious thought and emotions — they really believe that these whales have the ability to mourn and feel the sense of loss the same way that we do,” Brownlow says. “So there’s this incredible connection that the audience has with this story.”

Scientists also know that plastic in the water can combine with other industrial pollutants to form a toxic chemical cocktail. The heartbreaking theory: “When you have top predators like pilot whales, they accumulate over time high levels of toxins as they feed on the fish and squid and things that themselves have fed on all these different levels of the food chain that have accumulated these toxins. It leads to these lethal doses. When they suckle their newborns, they can actually be poisoned by their mother’s contaminated milk,” Brownlow says.

That familial bond is a happier story in a sperm whale sequence. The team worked with a cameraman who had been filming a particular pod of sperm whales off Mauritius for more than six years. One of the most beautiful, peaceful shots of all of Blue Planet II is the pod resting, floating vertically in the water. A calf, estimated to be about 2 weeks old, communicates to its slumbering mother that it’s hungry through a series of clicking sounds. “They’ve learned to accept him, and it enabled him to get incredibly intimate portrait details in a way that you’ve never seen before,” Brownlow says.

Scientists from The Dominica Sperm Whale Project have studied families of sperm whales since 2005, but for the first time, with Blue Planet II, they were able to put a sucker cam on the back of a sperm whale they knew by name, Fingers, to see how she dove with her calf, Digits. The camera, which detaches on its own after 30 hours, records video, sound, and scientific data. As the video above shows, you can see how closely the calf sticks to its mother, touching her repeatedly (“as if for reassurance,” Attenborough says). Because a calf can’t hold its breath as long as adults, it has to return to the surface and wait — sometimes as long as an hour — for its mother to finish hunting squid, which gives her the energy to produce milk.

Avid nature series viewers may find themselves tensing — we know calves are often prey. “You could say that sperm whales are the largest carnivore on the planet and you’d think they’re invincible, but the calves are subject to attack by pilot whales and killer whales,” Brownlow says. “When they are left at the surface, you do kind of fear for them, but they do communicate, send clicks out to their mother and the rest of the family. They are very social and protective. Sometimes they even leave a sort of nanny relative to nurse them whilst the others all dive in the deep.”

Blue Planet II was also able to place a sucker cam on a pregnant whale shark, revealing how silky sharks will bounce against her rough skin, perhaps to rid themselves of parasites. The goal is to find out where whale sharks give birth, to make sure those waters — and the migration route — are protected. “It’s extraordinary: This summarizes how little we still know about the ocean and its creatures. Here we have the largest fish of all, and we still don’t absolutely know where it gives birth to its pups,” Brownlow says. Though Jonathan Green of the Galapagos Whale Shark Project believes he’s close to a discovery at Darwin Island (which is explored more in Blue Planet II‘s seventh episode, “Our Blue Planet”). As Brownlow explains, “These pregnant whale sharks are indeed turning up to this tiny pinprick of an island in the Galápagos, for literally just two or three days, having swam across the Pacific Ocean. Then they just disappear after three days, but during that time they appear to have all gone down to the base of Darwin’s Arch, we think to give birth.”

“The boiling sea.” (GIF: BBC America)

Another great search, which is chronicled in the making-of segment at the end of this episode, was the Blue Planet II crew’s quest to film the phenomenon known as “the boiling sea,” a rare event fishermen and scientists have documented but no one has ever filmed. The sea literally erupts with whitewater as yellowfin tuna jump at the surface preying on a shoal of spawning lanternfish, which has been herded upward by hundreds of hungry spinner dolphins.

“It’s a nail-biting endeavor making a film of the open ocean, because finding your subjects is extremely hard. You’re combing this huge area of ocean every time, as opposed to let’s say a coral reef where you can work with scientists who’ve even identified individual fish that do these pieces of amazing behavior,” Brownlow says. “So it’s not for the faint-hearted, but if you put in the time, the effort, and stick with your conviction, more often than not you are rewarded.”

Spinner dolphins herd lanternfish. (GIF: BBC America)

After one failed expedition trip off the coast of Australia — it was the start of El Niño, when the sea temperatures rise to a point that disrupts the spawning behavior — the team had to wait 18 months until conditions improved to try again. This time, they traveled to Costa Rica to search for the dolphins first. It took 10 days in a helicopter for Brownlow to spot a pod, and another three weeks until the team was finally able to film them in “boiling sea” action.

“Euphoric joy!” is how he describes that moment. “You can’t really relax until you’ve filmed it, because it’s one thing eventually hitting upon the event, the other thing is then, Christ, it could be over in 10, 15 minutes. So we have to make sure that we cover it the very best way that we can. And sure enough, we were able to get action from both above from the helicopter, and underwater from the divers,” Brownlow says.

You’ll feel as though you’re part of the pursuit and the frenzy. “All these predators know that the lanternfish will only be at the surface momentarily, so they all have to race to get to the prize before it disappears again into the deep,” Brownlow says. “I wanted to reflect that in the way that we filmed it, that’s why we had to develop these camera systems that would enable us to fly alongside the dolphins and tuna as they are charging toward the bait ball. And then once [two cameramen with handhelds are] in the water, being in the middle of 40-mile-an-hour underwater torpedoes — these tuna are massive and they could knock you out, but they are so agile and they know exactly where you are, so they don’t actually run into you. Thank God.”

As always, the music in this episode is memorable as well. Hans Zimmer and the team at Bleeding Fingers particularly outdid themselves in the feeding Portuguese man-of-war sequence above. “That particular sequence was an homage to Pirates of the Caribbean, which of course Hans composed,” Brownlow says. “We wanted to have a bit of fun at that point. Of course this is a documentary — all we’re showing is truth and science — but at the same time, we want to build a connection with these characters with the audience, and music acts as our bridge. We wanted people not to feel coldly toward this sort of alien-like Portuguese man-of-war, but give it a bit of personality through the music. That’s what’s so incredible about Hans. He can make something profoundly moving, like the pilot whale sequence, through music, and then have great, great comedy like with the Pirates of the Caribbean music for the Portuguese man-of-war. Music has that ability to help to build these connections, and Hans is the master.”